Field of the Invention
The present invention relates to a motor controlling system in which positioning of a stepping motor can be performed.
Further in detail, the present invention controls a stepping motor, which is used to drive, for example, a carriage of an electronic typewriter, to be always to be set at a predetermined rotational position.
Description of the Prior Art
Hitherto, in known motor controlling systems when a stepping motor is to be set at a certain particular position (for instance, in case of an electronic typewriter, when the carriage is moved to the home position), there has been adopted a method whereby after the stepping motor passes through the particular position, it is rotated by only a constant or predetermined number of steps and is stopped, or the motor is stopped at a constant or predetermined excitation phase. In the former case, an error of .+-.1 step maybe caused because of lack of mechanical precision in detecting passage through the particular position. On the other hand, in the latter case, such an error is not caused because the motor is stopped at the predetermined phase after detection of passage through the particular position and a certain imprecision in such detection can therefore be tolerated. However, it is necessary to adjust the detecting mechanism, such as a home position sensor, for detecting passage of the motor through the particular position to be certain that the mechanism is not positioned at the boundary of the predetermined excitation phase.